Guide for drill collar subs



May 5,1959 J. JJBURRIS GUIDE FOR DRILL COLLAR SUBS 2 Sheets-Sheet 1 Filed Jan. 14, 1957 y K i in a M 4 M 2 w x M .L w i Z w K an 2 J J M dose oh 1 flair/s ATTORNEY May 5, 1959 J. J. BURRIS v GUIDE FOR DRILL COLLAR SUBS 2 S heets-Sh eet 2 Filed Jan. 14, 1957 H I H I 4 U I I I J I a m a y 8 a M w 2 z, j n W J w v H /0 l0 MI a a a v. a k 2 J 4 2 J M EQNI' lllll I8 4 5 v J N r. u 5 J n M/ w u INVENTOR.

Uniteci States hater? 2,sss,1ss GUIDE FoR DRILL COLLAR SUBS Jose h 'J. Burris, Livingston, Tex. Application January 14, 1957, Serial No. 634,042 a claims. (cl. 255 -2 8) This invention relates to a guide for drill collar subs and more particularly to a device which is adapted to be applied to a drilling string used in the drilling of wells for the purpose of guiding a drill collar sub in said string past a formation in a well bore, such as a key seat or other obstruction therein.

In the carrying out of well drilling operations and especially in the drilling of oil wells it is customary to employ a drilling string to whose lower end a bit is attached by means of a drill collar and drill collar sub. The drill collar or collars in such a string is customarily of smaller external diameter thanthe bit and the string above the drill collar sub is of substantially smaller external diameter than the drill collar. Due to the fact that the bore of the well is usually not straight, the drill string often is in contact with the wall of the bore at some locations therein, which results in the formation of longitudinal grooves, commonly called key seats which are of substantially smaller diameter than that of the bore. The presence of such key seats in a well bore presents a serious difiiculty in the removal of the drill string in that the string has a tendency to straighten out under its own weight and that of the drill collars and bit upon the exertion of an upward pull on the string, so that the drill collar sub or drill collar may enter the key seat and become stuck therein.

Heretofore, a drill collar sub has been frequently employed whose upper end is substantially of the same external diameter as that of the drill string and which is formed with a gradual taper to an external diameter substantially equal to that of the drill collar. A drill collar sub of this type has no abrupt changes in diameter and possesses the advantages of increased strength and resistance to breakage or twisting off under the stress encountered in the drilling operation. Because of its tapering shape, however, drill collar subs of this type have the disadvantage that they may easily enter and become wedged in a key seat causing the drill string to become stuck in the well bore. This disadvantage of the tapering drill collar sub has resulted in the abandonment of its use in many instances despite its obvious advantages of strength and durability.

The present invention has for an important object the provision of a guide for drill collar subs whereby the above disadvantage of a tapered drill collar sub may be overcome, and whereby a jarring action may be performed, if necessary to release the drill string in the event of sticking in a key seat.

Another object of the invention is to provide a guide for tapered drill collar subs whereby the advantages of a tapered sub may be secured without the attendant hazard of the same becoming stuck in the well bore.

A further object of the invention is the provision of a guide for drill collar subs, which permits the use of a tapered drill collar'sub, said guide embodying a sleeve adapted to be mounted on the sub to permit relativelongitudinal movement of the sub and sleeve and said sleeve having an external tapering surface positioned to operate 2,885,183 H Patented May 5, 1959 nice 2 as a guide to prevent the sticking of the sub in a key seat or other formation forming an obstruction in the well bore. J

Another object of the invention is to provide a c0ni bined drill collar sub and guide therefor wherein the s'u b' has a number of portions of different external diameters forming one or more external, annular, upwardly facing shoulders spaced apart longitudinally of the sub and the guide is of sleeve-like formation having one or more in ternal faces positioned for engagement with one or more of said shoulders to limit the relative longitudinal movement in one direction between the guide and sub.

A further object of the invention is the provision of a guide for drill collar subs which is of sleeve-like formation and relatively light construction and which has an external tapering surface positioned to serve as a guide to engage the wall of a well bore to guide the sub past a key-seat in the bore whereby sticking of the sub in the key-seat is prevented.

The above and other important objects and advantages of the invention may best be understood from the following detailed description constituting a specification of the same, when considered in conjunction with the annexed drawings, wherein Figure 1 is a vertical, cross-sectional View of a portion of a well bore showing a preferred embodiment of the invention in position therein and illustrating the manner in which the invention operates to guide a drill collar sub past a key seat in the bore; I

Figure 2 is a view similar to that of Figure 1 illustrating a somewhat modifiedv form of the invention;

Figure 3 is a cross-sectional view, taken along the line 3-3 of Figure 1, looking in the direction indicated by the arrows;

Figure 4 is a fragmentary, side elevational view, partly in cross-section of a somewhat difierent embodiment of the invention; and, I

Figure 5 is a view similar to that of Figure 4 illustrating a further modification of the invention.

Referring now to the drawings in greater detail, the invention is illustrated in connection with its use with a tubular drilling string of the usual type, the numeral 10 designating a tool joint on the lower section of such a string, to the lower end of which a drill collar sub 12 is connected and which is in turn connected to one or more drill collars, such as that shown at 14 attached to a drilling bit 16of conventional design.

The drilling string, made up in the manner described above is employed in the drilling of wells in the customary manner, the bore of such awell being illustrated at W in Figures 1, 2 and 3, with the string in position therein.

In the drilling of a well by the use of equipmentof this kind key seats such as that shown at K are often produced, due to curvature of the well bore, which causes the drilling string to be rotated incontact with the wall of the bore thereby forming an elongated slot whose diameter is smaller than that of the well bore. When an upward pull is exerted on the drilling string, as when the same is being withdrawn from the well, the drilling string tends to straighten out under its own weight and that of the drill collars and bit, so that there is a tendency for the drill collar sub to enter such a key seat, which often results inthe drill collar becoming wedged in the key seat.

In the present invention the drill collar sub 12 has an upper end portion 18-whose external diameter is somewhat smaller than the external diameter of the tool joint wand which may be externally threaded, as indicatedgat 20 for connection to the lower end of the drill pipe, whereby an external downwardly facingshoulder 22 is formed providing an upper impact face.

"If 4 l l engage external upwardly facing edwlthoneor be positioned to shoulders suchasthoueindicntedatd', nnd,to limit downward movementoftheguideelementonthe sub. The guide element may also be of a length such that the lower end of the guide element is in contact with or somewhat separated from the lower impact face 30 when the element reaches its lowermost position on the sub.

3 Beoeathtlnponion 18 is form m t. m m pmemc m cmmeimwm .mmmmn mm dnmmw tm fm n mmh .mrc ummm flm mm m mm mmmm .m amm we may wwm m mmfim wm fim mw wmm m m mmmm mmmm Wm meme. m Mmmmm mmmm mmfixmmm mmmm? 3 u wu .w w m mw m m w w mmfim mm wmw m m w mim w m .m e p m L. 1% w im? n w mum W n15 3km; mmmfmaw w w t m mm m m mmmmmmm m mmm ME?nmm w m mxmmwmm w m mm m w mwmimmm u m mM m m mmmwmmmm @Jm. m W W MWWW t m wm mwmmm mmmwummmwt tmdm mqmmm m m mm mm m mmmmmmmfi mmH Wm m fi mw wmmmmum m m um mmmmm m mmmmmm mmmMw mmmmmwm mmmmmmmmm mymww mmm wmm W mwmmw m inumw mmwnmww mmmm ammm m m m m m wu mnm .m wmmm W t m a m be m w n d W m wmfimmmm mmemw mmmmmmmmm mmmm mfimem m 1. .1 A W mm MP mmm w mwma u t m m n it t w m m w M M m mr v.u M do E M W M m m e w W m m? i t L m m .0... l h m w mmm MW m w mumm my. mm wmw w m f em fifi W m mmuwm W m m mm mww m m a Pmm ww mw mw mmuwmmm am 0 a mm mm fim m. am m 3 mm; dmwmmmhue w t m it we 4 mw m nm wh mm Mmm m Pm mmi w mm m mm M w Wmma w .4. t. w W M M m t mm H m m mm mm M m t mm m w my um om m wn u m um u t w M: 1a m v mm m mmmmu W m .m hmw mbwmh m m mdmw mmmwdmm mi d .m m m m m mu m M m it mwwm ww m -1mm mwmu a M mmmm it new M. M m w w mm Ma wm m it t t t it t H W t M t t t t t t it ow Hm mn mw M e u m M m m m m t m m t ME H w w t F we .3? FM??? WWERWmmm mmwtmm mwwmmmw m mama ly smaller than the external diameter of the tool joints of the string to provide an external downwardly facing impact face on the lower end of the string and a cylindrically shaped lower end portion Whose external diameter is substantially equal to the external diameter of the drill collar and whose upper end forms an external, annular, upwardly facing shoulder above the lower end of the sub, 21 tubular guide surrounding and movable longitudinally on the sub and having an upper end portion whose external di ameter is substantially equal to the external diameter of said tool joints and whose internal surface is shaped to slidingly fit the external surface of the upper end portion of the sub in all positions of the guide on the sub, and a lower end portion formed with an internal surface shaped to slidingly fit the external surface of said cylindrically shaped portion and whose external diameter is substantially equal to the external diameter of said drill collar, the external surface of said guide tapering upwardly between said upper and lower end portions of the guide and said guide being formed with an internal annular shoulder positioned for engagement with said external shoulder to limit downward movement of the guide on the sub and being of a length substantially greater than the distance between said impact face and said external shoulder and such that the lower end of said guide is below said external shoulder in all positions of the guide on said sub.

3. Well drilling equipment comprising a tubular drill string, a drill collar sub connected to said string and a drill collar connected to said sub, said sub having an upper end portion whose external diameter is substantially smaller than the external diameter of the tool joints of the string to provide an external downwardly facing impact face on the lower end of the string and a cylindrical- 1y shaped lower end portion whose external diameter is substantially equal to the external diameter of the drill collar and whose upper end forms an external, annular, upwardly facing shoulder above the lower end of the sub, a tubular guide surrounding and movable longitudinally on the sub and having an upper end portion whose external diameter is substantially equal to the external diameter of said tool joints and whose internal surface is shaped to slidingly fit the external surface of the upper end portion of the sub in all positions of the guide on the sub, and a lower end portion formed with an internal surface shaped to slidingly fit the external surface of said cylindrically shaped portion and whose external diameter is substantially equal to the external diameter of said drill collar, the external surface of said guide tapering upwardly between said upper and lower end portions of the guide and said guide being formed with an internal annular shoulder positioned for engagement with said external shoulder to limit downward movement of the guide on the sub and being of a length substantially greater than the distance between said impact face and said external shoulder and such that the lower end of said guide is below said external shoulder in all positions of the guide on said sub, and external cutting means on said upwardly tapering surface of said guide.

Causes, Preventions, Recovery of Stuck Drill Pipe, I. E. Warren, Oil and Gas Journal, April 4, 1940, page 40. 

